We try to understand mechanism and physiological significance of carbohydrate-protein interactions in animals. A major emphasis will be place on hepatic sugar binding proteins. we will examine the molecular binding mechanism of rabbit hepatic Gal/GalNAc-binding protein, by interacting a series of neoglycoproteins having different sugars and aglycons with the binding protein. Affinity labelling with synthetic glycoside will be attemtped. Additionally, lactoperoxidase modified with Gal/GalNAc derivatives, a good ligand for the binding protein, will be used for selective iodination of the binding protein. Comparative biochemistry of hepatic sugar-binding proteins will be studied. Sugar-binding specificity of chicken liver non-parenchymal cells will be examined. Sugar-binding specificity from livers of lower vertebrates will be compared. Sugar-binding proteins from these animals will be isolated, characterized and comparedwith the known hepatic sugar-binding proteins. We will also study sugar-binding proteins in animal sera with respect to specificity, molecular properties, sand physiological behavior. The clearance of immunological complex by carbohydrate-mediated receptors will be studied in depth using monoclonal antibodies, well-defined antigens, and mammalian hepatocytes and alveolar macrophages. We will also determine when the hepatic GlcNAc-binding activity is expressed during the developmental stages of chick embryo and juvenile chicken.